Tamper proof envelope

ABSTRACT

An envelope which cannot be opened by unauthorized persons after being sealed, without exhibiting signs of such tampering. In one form, the top flap portion carries a bonding layer on its lower margin when it overlies the bottom flap and left and right side flaps, which is heat-sealable, by application of a hot ironing iron thereon, to make a permanent &#39;&#39;&#39;&#39;iron-on&#39;&#39;&#39;&#39; type of seal, like used on &#39;&#39;&#39;&#39;iron-on&#39;&#39;&#39;&#39; garment patches. Another form of the envelope uses ordinary mucilage containing a dye which changes color on application of hot steam to steam it open, so the recipient can know that someone has steamed it open.

McCarthy TAMPER PROOF ENVELOPE 14 1 July 22, 1975 PrimaryExaminer-William I. Price I t: C 1S.MC th,A l,Md. [75] men or am 6 at ynnapo ls Assistant ExammerStephen P. Garbe Assigneel Lawrence PeskaAssociates, Attorney, Agent, or Firm-Richard E. Nanfeldt New York, N.Y.a part interest [22] Filed: Feb. 27, 1974 [57] ABSTRACT [21] A N 446,283An envelope which cannot be opened by unauthorized persons after beingsealed, without exhibiting signs of such tampering. In one form, the topflap portion 0.8. Carries a bonding layer on its lower margin when itCl. r overlies the bottom fl p and left and right side flap [58] Fieldof Search 229/80, 83, 117/1, 1.5, which is heapsealable by applicationof a hot ironing 8/7 iron thereon, to make a permanent iron-on" type ofseal, like used on iron-on garment patches. Another [56] ReferencesC'ted form of the envelope uses ordinary mucilage contain- UNITED ST P Ting a dye which changes color on application of hot 883,364 3/l908Walter 229/83 steam to steam it open, so the recipient can know thatl,20l,5l9 lO/l9l6 Sorensen 229/83 X someone has steamed it open.2,032,386 3/1936 Wood 229/83 X 2,277,116 3/1942 Krueger 229/80 1 Clalm,5 Drawing Flgures i 22 4 l y (\1 10 3 32 32 to the flapthat the paperhas to be torn in order to open it, and'hence is detectable.

A further object of the invention is to provide a novel and improvedenvelope construction in which the adhesion of the flap with the rest ofthe envelope is caused by application of the iron-on principle ofadhesion, which is commonly used for so-called iron-on patches forgarments, slacks, elbow patches, knee patches and the like, which aresecured in place by placing the patch over the tear or hole, and using ahot ironing iron to cause the patch to adhere firmly to the garment, andbeing so strong that it can withstand laundering, dry cleaning and otherusages without coming loose.

Still a further object of the invention is to provide a novel andimproved envelope construction, in which the adhesive used contains achemical ingredient of a neutral color, but which will change color ifsubjected to steam or other heat being used to steam it open, so thatthe tampering is immediately noticed by the addressee or recipient ofthe letter.

Still another object of the invention is to provide a novel and improvedtamper-proof envelope construction which is simple in design, looks verymuch like an ordinary envelope, and which can be made at low cost bymass production methods.

The above and other objects and advantages of the invention, will becomeapparent from the following description of a preferred embodimentthereof, as illustrated in the accompanying drawings, forming a parthereof.

IN THE DRAWINGS FIG. 1 is a face view of an envelope according to theinvention, and employing a heat-seal type of bonding material, the flapbeing in open position.

FIG. 2 is a side elevational view of an ironing iron as used forsubjecting the envelope of FIG. 1 to the heat sealing bonding sealingoperation.

FIG. 3 is a face view of an envelope in which the flap has been closedand secured in closed position by heatsealing or iron-on procedure.

FIG. 4 is a face view of an envelope construction in which the adhesivematerial for securing the flap to the body of the envelope is aheat-sensitive two color dyecontaining adhesive which is of one color onbeing used to seal the envelope, and another if heat or steam is used totamper with it.

FIG. 5 is a face view of the envelope of FIG. 4, showing how theheat-sensitive two color dye-containing adhesive of FIG. 4 changes toanother color on application of heat or steam in tampering therewith toshow clearly the tampering.

. In connection with the use of envelopes and other packaging forletters, manuscripts, booklets, and the like in mailing or sending bymessenger, parcel post, ex-

press or other means of transportation, it is important that thecontentsnot be disturbed or tampered with by unauthorized persons whilethis is necessary to guard against where the contents are valuableobjects, such as jewelry, it is also just as important where thecontents are letters, memoranda, manuscripts, song sheets, drafts orproposed lectures and the like.

The important object is to first make it very difficult for an intruderto open the package or envelope to inspect the contents, and if this isdone, to make it self evident that the package or envelope has beenopened, so that the sender and addressee at least know that anunauthorized person has opened the package or envelope, and also to tryto ascertain or guess who it is, and to apprehend him or her. Thepresent invention seeks to provide such an envelope or packaging means;for obtaining the above protection.

In order to understand clearly the nature of the invention and the bestmeans for carrying it out, references may be had to the drawings, inwhich like numerals denote similar parts throughout the several views.

As shown, there is an envelope 10, formedof sheet material such aspaper, cardboard, bristol board, sheet plastics, or other flexiblematerial suitable for containing a letter, or other contents formailing, delivering by messenger, or other means. Such an envelope 10may have a main body face wall 12, with left and right side edges 14 and16, and front and rear edges 18 and 20, with integral folded left andright flap portions 22 and 24, folded under a bottom flap portion 26 toform an envelope pocket or receptacle 28, for the reception of a letter,memorandum, notice, card or other material or a pamphlet or bookletbeing sent to the addressee.

For closing the envelope pocket there is top flap portion 30, which isalso integral with the main envelope body face wall 12, like the otherflap portions mentioned, and which may be folded downwardly to overlapthe borders of the remaining flap portions, in the manner shown in FIGS.2 and 3, to close the envelope and seal in the contents.

An adhesive layer of material or glue or mucilage 32 is placed under theupper marginal areas of the bottom flap portion 26 where it overlaps theside flaps 22 and 24, so as to be firmly secured thereto to seal thebottom of the envelope pocket. The top flap portion 30 is provided withborder layers 34 of heat-seal bonding adhesive on its lower marginalsurfaces where it overlaps the bottom flap portion and the two side flapportions, so as to firmly adhere to them all. This firmly seals theenvelope pocket against unauthorized opening to inspect its contents,without tearing the envelope open, for, as shown in FIG. 2, an electricironing iron 36 is heated up and used to iron the envelope top flap tofirmly bond to the underlying flap portions by heat sealing, the heatcausing the adhesive material to flow and meld or join the flapstogether in a good seal bond.

Such iron-on bonding materials are well known in the garment repair art,being widely sold in notion and department stores for repairing tearsand rips in garments, and for also attaching knee and elbow patches forgreater wear and also for giving a special appearance with the presentday fashions which encourage such appliques for novelty.

This bonding material may also be used for the other adhesive areas suchas 32 with the other flap portions if desired, for further sealingprotection, so that the iron heat seals them together also.

As shown in FIGS. 4 and 5, where the envelopes use ordinary glue ormucilage in the adhesive areas 32 to connect the bottom flap to the leftand right side flaps, and such mucilage at 40A is applied as a layeralong the marginal edges of the top flap portion 30A where they willoverlie the marginal edge portions of the bottom and side flaps, themucilage or adhesive will look much like ordinary adhesive which ismoistened before sealing the envelope and pressed down to adhere and toseal the envelope. However, to make plain any tampering or steaming openof the envelope by unauthorized persons, the'adhesive mucilage or glue40A contains a heat sensitive die material which changes color whensteam heat is applied to the envelope to steam it open, as shown in FIG.5 at 408. Such heat-sensitive dyes are well known in the dye andcoloring arts, such as in the cloth and fabric manufacturing arts wherethe cloth or yarn is impregnated with liquid containing the heatsensitive dye, and at a later stage of manufacture is dipped into a hotbath or subjected to live steam, to bring out the desired color and tofix it to the fabric or yarn.

Thus the adhesive 40A of FIG. 4 would turn to some color such as red orgreen, when steam is applied to steam it open, and this would indicateto the recipient that the envelope had been tampered with even thoughadditional glue or mucilage was applied to reseal the envelope. Whilethis would not prevent tampering with the mail, it would at least letthe recipient know that someone other than the sender had read thecontents.

While the invention has been set forth in specific terms, it isunderstood that various changes may be made in size, shape, materialsand arrangements without departing from the spirit and scope of theinvention as claimed.

Having herein described the invention, what is claimed as new is:

l. A tamper proof envelope, which comprises:

a. a main body face wall having a left, a right, a front and a rearedge;

b. a left, a right, and a bottom flap portion integrally formed to saidmain body face, said left and said right flap portions folded under andsealed to said bottom flap portion forming an envelope pocket;

c. a top flap portion having a marginal edge, said top 1 flap portionintegrally formed to said main body face; and

d. an integral mixture of a heat sensitive dye and an adhesive materialwhich becomes adhesive on application of moisture, said mixturedeposited as a single layer on said marginal edge of said top flapportion, said mixture forming a bond between said top flap portion andsaid left, said right and said bottom flap portion, said dye changingcolor upon the application of a heat means.

1. A tamper proof envelope, which comprises: a. a main body face wallhaving a left, a right, a front and a rear edge; b. a left, a right, anda bottom flap portion integrally formed to said main body face, saidleft and said right flap portions folded under and sealed to said bottomflap portion forming an envelope pocket; c. a top flap portion having amarginal edge, said top flap portion integrally formed to said main bodyface; and d. an integral mixture of a heat sensitive dye and an adhesivematerial which becomes adhesive on application of moisture, said mixturedeposited as a single layer on said marginal edge of said top flapportion, said mixture forming a bond between said top flap portion andsaid left, said right and said bottom flap portion, said dye changingcolor upon the application of a heat means.